The purpose of this contract is to provide the services of a reading center to interpret cerebral magnetic resonance images (MRI) performed in the epidemiological research study of the major factors contributing to the occurrence of cardiovascular disease in middle-aged adults entitled "Atherosclerosis Risk in Communities Study (ARIC)." The MRI Reading Center will assist in protocol development for the performance of cerebral MRI on 2,000 participants at two of the ARIC Field Centers located in Jackson, Ms and Forsyth County, NC; and will perform measurements and interpretations of these images in a standardized and reproducible manner. Atherosclerosis Risk in Communities (ARIC), a study of cardiovascular diseases in four U.S. communities among men, women, blacks and whites, has two primary objectives: (1) to investigate factors associated with both atherosclerosis and incidence of clinical cardiovascular diseases, and (2) to measure coronary heart disease (CHD) occurrence and trends and relate them to community levels of risk factors, medical care and atherosclerosis. Operationally, the study includes both surveillance for coronary disease among all residents aged 35-74 of the four communities and follow-up of cohorts of 4,000 persons aged 45-64 at first examination (which occurred in 1987-1990) selected to represent each community. The study communities are Forsyth County, North Carolina, Jackson, Mississippi, suburbs of Minneapolis, Minnesota, and Washington County, Maryland.